Businessman Donald Trump announced June 16 at his Trump Tower in New York City that he is seeking the Republican presidential nomination. This ends more than two decades of flirting with the idea of running for the White House.

"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement.

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Sen. Ted Cruz of Texas has made a name for himself in the Senate, solidifying his brand as a conservative firebrand willing to take on the GOP's establishment. He announced he was seeking the Republican presidential nomination in a speech on March 23.

"These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant."

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Ohio Gov. John Kasich joined the Republican field July 21 as he formally announced his White House bid.

"I am here to ask you for your prayers, for your support ... because I have decided to run for president of the United States," Kasich told his kickoff rally at the Ohio State University.

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Hillary Clinton launched her presidential bid on April 12 through a video message on social media. The former first lady, senator and secretary of state is considered the front-runner among possible Democratic candidates.

"Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey."

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Sen. Bernie Sanders, an independent from Vermont who caucuses with Democrats, announced his run in an email to supporters on April 30. He has said the United States needs a "political revolution" of working-class Americans to take back control of the government from billionaires.

"This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26.

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"Well, I'm not a masochist," Trump said. "Right now I'm leading every poll, and in most cases big. That's good. If that changed, if I was like some of these people at 1% and 2%, there's no reason to continue forward. If I fell behind badly, I would certainly get out."

He said he isn't planning to return to his business empire soon.

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"I'm in this for the long haul," Trump said. "That doesn't mean someday I don't wake up and I say, 'Wow, I'm really tanking.' Well, if I tank, sure, I go back to the business. Why wouldn't I?"

In pressing Trump on how he'd accomplish many of his campaign goals -- like deporting 11 million undocumented immigrants -- Harwood said, "We don't have Superman presidents."